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Linux 5.10.7
[linux/fpc-iii.git] / scripts / mod / modpost.c
blobf882ce0d9327f857049e914196b2e03c38dea9b1
1 /* Postprocess module symbol versions
2 *
3 * Copyright 2003 Kai Germaschewski
4 * Copyright 2002-2004 Rusty Russell, IBM Corporation
5 * Copyright 2006-2008 Sam Ravnborg
6 * Based in part on module-init-tools/depmod.c,file2alias
7 *
8 * This software may be used and distributed according to the terms
9 * of the GNU General Public License, incorporated herein by reference.
10 *
11 * Usage: modpost vmlinux module1.o module2.o ...
12 */
13
14 #define _GNU_SOURCE
15 #include <elf.h>
16 #include <stdio.h>
17 #include <ctype.h>
18 #include <string.h>
19 #include <limits.h>
20 #include <stdbool.h>
21 #include <errno.h>
22 #include "modpost.h"
23 #include "../../include/linux/license.h"
24
25 /* Are we using CONFIG_MODVERSIONS? */
26 static int modversions = 0;
27 /* Warn about undefined symbols? (do so if we have vmlinux) */
28 static int have_vmlinux = 0;
29 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
30 static int all_versions = 0;
31 /* If we are modposting external module set to 1 */
32 static int external_module = 0;
33 /* Only warn about unresolved symbols */
34 static int warn_unresolved = 0;
35 /* How a symbol is exported */
36 static int sec_mismatch_count = 0;
37 static int sec_mismatch_fatal = 0;
38 /* ignore missing files */
39 static int ignore_missing_files;
40 /* If set to 1, only warn (instead of error) about missing ns imports */
41 static int allow_missing_ns_imports;
42
43 enum export {
44 export_plain, export_unused, export_gpl,
45 export_unused_gpl, export_gpl_future, export_unknown
46 };
47
48 /* In kernel, this size is defined in linux/module.h;
49 * here we use Elf_Addr instead of long for covering cross-compile
50 */
51
52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
53
54 void __attribute__((format(printf, 2, 3)))
55 modpost_log(enum loglevel loglevel, const char *fmt, ...)
56 {
57 va_list arglist;
58
59 switch (loglevel) {
60 case LOG_WARN:
61 fprintf(stderr, "WARNING: ");
62 break;
63 case LOG_ERROR:
64 fprintf(stderr, "ERROR: ");
65 break;
66 case LOG_FATAL:
67 fprintf(stderr, "FATAL: ");
68 break;
69 default: /* invalid loglevel, ignore */
70 break;
71 }
72
73 fprintf(stderr, "modpost: ");
74
75 va_start(arglist, fmt);
76 vfprintf(stderr, fmt, arglist);
77 va_end(arglist);
78
79 if (loglevel == LOG_FATAL)
80 exit(1);
81 }
82
83 static inline bool strends(const char *str, const char *postfix)
84 {
85 if (strlen(str) < strlen(postfix))
86 return false;
87
88 return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
89 }
90
91 void *do_nofail(void *ptr, const char *expr)
92 {
93 if (!ptr)
94 fatal("Memory allocation failure: %s.\n", expr);
95
96 return ptr;
97 }
98
99 char *read_text_file(const char *filename)
100 {
101 struct stat st;
102 size_t nbytes;
103 int fd;
104 char *buf;
105
106 fd = open(filename, O_RDONLY);
107 if (fd < 0) {
108 perror(filename);
109 exit(1);
110 }
111
112 if (fstat(fd, &st) < 0) {
113 perror(filename);
114 exit(1);
115 }
116
117 buf = NOFAIL(malloc(st.st_size + 1));
118
119 nbytes = st.st_size;
120
121 while (nbytes) {
122 ssize_t bytes_read;
123
124 bytes_read = read(fd, buf, nbytes);
125 if (bytes_read < 0) {
126 perror(filename);
127 exit(1);
128 }
129
130 nbytes -= bytes_read;
131 }
132 buf[st.st_size] = '\0';
133
134 close(fd);
135
136 return buf;
137 }
138
139 char *get_line(char **stringp)
140 {
141 char *orig = *stringp, *next;
142
143 /* do not return the unwanted extra line at EOF */
144 if (!orig || *orig == '\0')
145 return NULL;
146
147 /* don't use strsep here, it is not available everywhere */
148 next = strchr(orig, '\n');
149 if (next)
150 *next++ = '\0';
151
152 *stringp = next;
153
154 return orig;
155 }
156
157 /* A list of all modules we processed */
158 static struct module *modules;
159
160 static struct module *find_module(const char *modname)
161 {
162 struct module *mod;
163
164 for (mod = modules; mod; mod = mod->next)
165 if (strcmp(mod->name, modname) == 0)
166 break;
167 return mod;
168 }
169
170 static struct module *new_module(const char *modname)
171 {
172 struct module *mod;
173
174 mod = NOFAIL(malloc(sizeof(*mod) + strlen(modname) + 1));
175 memset(mod, 0, sizeof(*mod));
176
177 /* add to list */
178 strcpy(mod->name, modname);
179 mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
180 mod->gpl_compatible = -1;
181 mod->next = modules;
182 modules = mod;
183
184 if (mod->is_vmlinux)
185 have_vmlinux = 1;
186
187 return mod;
188 }
189
190 /* A hash of all exported symbols,
191 * struct symbol is also used for lists of unresolved symbols */
192
193 #define SYMBOL_HASH_SIZE 1024
194
195 struct symbol {
196 struct symbol *next;
197 struct module *module;
198 unsigned int crc;
199 int crc_valid;
200 char *namespace;
201 unsigned int weak:1;
202 unsigned int is_static:1; /* 1 if symbol is not global */
203 enum export export; /* Type of export */
204 char name[];
205 };
206
207 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
208
209 /* This is based on the hash agorithm from gdbm, via tdb */
210 static inline unsigned int tdb_hash(const char *name)
211 {
212 unsigned value; /* Used to compute the hash value. */
213 unsigned i; /* Used to cycle through random values. */
214
215 /* Set the initial value from the key size. */
216 for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
217 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
218
219 return (1103515243 * value + 12345);
220 }
221
222 /**
223 * Allocate a new symbols for use in the hash of exported symbols or
224 * the list of unresolved symbols per module
225 **/
226 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
227 struct symbol *next)
228 {
229 struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
230
231 memset(s, 0, sizeof(*s));
232 strcpy(s->name, name);
233 s->weak = weak;
234 s->next = next;
235 s->is_static = 1;
236 return s;
237 }
238
239 /* For the hash of exported symbols */
240 static struct symbol *new_symbol(const char *name, struct module *module,
241 enum export export)
242 {
243 unsigned int hash;
244
245 hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
246 symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
247
248 return symbolhash[hash];
249 }
250
251 static struct symbol *find_symbol(const char *name)
252 {
253 struct symbol *s;
254
255 /* For our purposes, .foo matches foo. PPC64 needs this. */
256 if (name[0] == '.')
257 name++;
258
259 for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
260 if (strcmp(s->name, name) == 0)
261 return s;
262 }
263 return NULL;
264 }
265
266 static bool contains_namespace(struct namespace_list *list,
267 const char *namespace)
268 {
269 for (; list; list = list->next)
270 if (!strcmp(list->namespace, namespace))
271 return true;
272
273 return false;
274 }
275
276 static void add_namespace(struct namespace_list **list, const char *namespace)
277 {
278 struct namespace_list *ns_entry;
279
280 if (!contains_namespace(*list, namespace)) {
281 ns_entry = NOFAIL(malloc(sizeof(struct namespace_list) +
282 strlen(namespace) + 1));
283 strcpy(ns_entry->namespace, namespace);
284 ns_entry->next = *list;
285 *list = ns_entry;
286 }
287 }
288
289 static bool module_imports_namespace(struct module *module,
290 const char *namespace)
291 {
292 return contains_namespace(module->imported_namespaces, namespace);
293 }
294
295 static const struct {
296 const char *str;
297 enum export export;
298 } export_list[] = {
299 { .str = "EXPORT_SYMBOL", .export = export_plain },
300 { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
301 { .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
302 { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
303 { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
304 { .str = "(unknown)", .export = export_unknown },
305 };
306
307
308 static const char *export_str(enum export ex)
309 {
310 return export_list[ex].str;
311 }
312
313 static enum export export_no(const char *s)
314 {
315 int i;
316
317 if (!s)
318 return export_unknown;
319 for (i = 0; export_list[i].export != export_unknown; i++) {
320 if (strcmp(export_list[i].str, s) == 0)
321 return export_list[i].export;
322 }
323 return export_unknown;
324 }
325
326 static void *sym_get_data_by_offset(const struct elf_info *info,
327 unsigned int secindex, unsigned long offset)
328 {
329 Elf_Shdr *sechdr = &info->sechdrs[secindex];
330
331 if (info->hdr->e_type != ET_REL)
332 offset -= sechdr->sh_addr;
333
334 return (void *)info->hdr + sechdr->sh_offset + offset;
335 }
336
337 static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
338 {
339 return sym_get_data_by_offset(info, get_secindex(info, sym),
340 sym->st_value);
341 }
342
343 static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
344 {
345 return sym_get_data_by_offset(info, info->secindex_strings,
346 sechdr->sh_name);
347 }
348
349 static const char *sec_name(const struct elf_info *info, int secindex)
350 {
351 return sech_name(info, &info->sechdrs[secindex]);
352 }
353
354 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
355
356 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
357 {
358 const char *secname = sec_name(elf, sec);
359
360 if (strstarts(secname, "___ksymtab+"))
361 return export_plain;
362 else if (strstarts(secname, "___ksymtab_unused+"))
363 return export_unused;
364 else if (strstarts(secname, "___ksymtab_gpl+"))
365 return export_gpl;
366 else if (strstarts(secname, "___ksymtab_unused_gpl+"))
367 return export_unused_gpl;
368 else if (strstarts(secname, "___ksymtab_gpl_future+"))
369 return export_gpl_future;
370 else
371 return export_unknown;
372 }
373
374 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
375 {
376 if (sec == elf->export_sec)
377 return export_plain;
378 else if (sec == elf->export_unused_sec)
379 return export_unused;
380 else if (sec == elf->export_gpl_sec)
381 return export_gpl;
382 else if (sec == elf->export_unused_gpl_sec)
383 return export_unused_gpl;
384 else if (sec == elf->export_gpl_future_sec)
385 return export_gpl_future;
386 else
387 return export_unknown;
388 }
389
390 static const char *namespace_from_kstrtabns(const struct elf_info *info,
391 const Elf_Sym *sym)
392 {
393 const char *value = sym_get_data(info, sym);
394 return value[0] ? value : NULL;
395 }
396
397 static void sym_update_namespace(const char *symname, const char *namespace)
398 {
399 struct symbol *s = find_symbol(symname);
400
401 /*
402 * That symbol should have been created earlier and thus this is
403 * actually an assertion.
404 */
405 if (!s) {
406 merror("Could not update namespace(%s) for symbol %s\n",
407 namespace, symname);
408 return;
409 }
410
411 free(s->namespace);
412 s->namespace =
413 namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
414 }
415
416 /**
417 * Add an exported symbol - it may have already been added without a
418 * CRC, in this case just update the CRC
419 **/
420 static struct symbol *sym_add_exported(const char *name, struct module *mod,
421 enum export export)
422 {
423 struct symbol *s = find_symbol(name);
424
425 if (!s) {
426 s = new_symbol(name, mod, export);
427 } else if (!external_module || s->module->is_vmlinux ||
428 s->module == mod) {
429 warn("%s: '%s' exported twice. Previous export was in %s%s\n",
430 mod->name, name, s->module->name,
431 s->module->is_vmlinux ? "" : ".ko");
432 return s;
433 }
434
435 s->module = mod;
436 s->export = export;
437 return s;
438 }
439
440 static void sym_set_crc(const char *name, unsigned int crc)
441 {
442 struct symbol *s = find_symbol(name);
443
444 /*
445 * Ignore stand-alone __crc_*, which might be auto-generated symbols
446 * such as __*_veneer in ARM ELF.
447 */
448 if (!s)
449 return;
450
451 s->crc = crc;
452 s->crc_valid = 1;
453 }
454
455 static void *grab_file(const char *filename, size_t *size)
456 {
457 struct stat st;
458 void *map = MAP_FAILED;
459 int fd;
460
461 fd = open(filename, O_RDONLY);
462 if (fd < 0)
463 return NULL;
464 if (fstat(fd, &st))
465 goto failed;
466
467 *size = st.st_size;
468 map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
469
470 failed:
471 close(fd);
472 if (map == MAP_FAILED)
473 return NULL;
474 return map;
475 }
476
477 static void release_file(void *file, size_t size)
478 {
479 munmap(file, size);
480 }
481
482 static int parse_elf(struct elf_info *info, const char *filename)
483 {
484 unsigned int i;
485 Elf_Ehdr *hdr;
486 Elf_Shdr *sechdrs;
487 Elf_Sym *sym;
488 const char *secstrings;
489 unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
490
491 hdr = grab_file(filename, &info->size);
492 if (!hdr) {
493 if (ignore_missing_files) {
494 fprintf(stderr, "%s: %s (ignored)\n", filename,
495 strerror(errno));
496 return 0;
497 }
498 perror(filename);
499 exit(1);
500 }
501 info->hdr = hdr;
502 if (info->size < sizeof(*hdr)) {
503 /* file too small, assume this is an empty .o file */
504 return 0;
505 }
506 /* Is this a valid ELF file? */
507 if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
508 (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
509 (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
510 (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
511 /* Not an ELF file - silently ignore it */
512 return 0;
513 }
514 /* Fix endianness in ELF header */
515 hdr->e_type = TO_NATIVE(hdr->e_type);
516 hdr->e_machine = TO_NATIVE(hdr->e_machine);
517 hdr->e_version = TO_NATIVE(hdr->e_version);
518 hdr->e_entry = TO_NATIVE(hdr->e_entry);
519 hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
520 hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
521 hdr->e_flags = TO_NATIVE(hdr->e_flags);
522 hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
523 hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
524 hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
525 hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
526 hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
527 hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
528 sechdrs = (void *)hdr + hdr->e_shoff;
529 info->sechdrs = sechdrs;
530
531 /* Check if file offset is correct */
532 if (hdr->e_shoff > info->size) {
533 fatal("section header offset=%lu in file '%s' is bigger than filesize=%zu\n",
534 (unsigned long)hdr->e_shoff, filename, info->size);
535 return 0;
536 }
537
538 if (hdr->e_shnum == SHN_UNDEF) {
539 /*
540 * There are more than 64k sections,
541 * read count from .sh_size.
542 */
543 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
544 }
545 else {
546 info->num_sections = hdr->e_shnum;
547 }
548 if (hdr->e_shstrndx == SHN_XINDEX) {
549 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
550 }
551 else {
552 info->secindex_strings = hdr->e_shstrndx;
553 }
554
555 /* Fix endianness in section headers */
556 for (i = 0; i < info->num_sections; i++) {
557 sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
558 sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
559 sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
560 sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
561 sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
562 sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
563 sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
564 sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
565 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
566 sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
567 }
568 /* Find symbol table. */
569 secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
570 for (i = 1; i < info->num_sections; i++) {
571 const char *secname;
572 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
573
574 if (!nobits && sechdrs[i].sh_offset > info->size) {
575 fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
576 "sizeof(*hrd)=%zu\n", filename,
577 (unsigned long)sechdrs[i].sh_offset,
578 sizeof(*hdr));
579 return 0;
580 }
581 secname = secstrings + sechdrs[i].sh_name;
582 if (strcmp(secname, ".modinfo") == 0) {
583 if (nobits)
584 fatal("%s has NOBITS .modinfo\n", filename);
585 info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
586 info->modinfo_len = sechdrs[i].sh_size;
587 } else if (strcmp(secname, "__ksymtab") == 0)
588 info->export_sec = i;
589 else if (strcmp(secname, "__ksymtab_unused") == 0)
590 info->export_unused_sec = i;
591 else if (strcmp(secname, "__ksymtab_gpl") == 0)
592 info->export_gpl_sec = i;
593 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
594 info->export_unused_gpl_sec = i;
595 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
596 info->export_gpl_future_sec = i;
597
598 if (sechdrs[i].sh_type == SHT_SYMTAB) {
599 unsigned int sh_link_idx;
600 symtab_idx = i;
601 info->symtab_start = (void *)hdr +
602 sechdrs[i].sh_offset;
603 info->symtab_stop = (void *)hdr +
604 sechdrs[i].sh_offset + sechdrs[i].sh_size;
605 sh_link_idx = sechdrs[i].sh_link;
606 info->strtab = (void *)hdr +
607 sechdrs[sh_link_idx].sh_offset;
608 }
609
610 /* 32bit section no. table? ("more than 64k sections") */
611 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
612 symtab_shndx_idx = i;
613 info->symtab_shndx_start = (void *)hdr +
614 sechdrs[i].sh_offset;
615 info->symtab_shndx_stop = (void *)hdr +
616 sechdrs[i].sh_offset + sechdrs[i].sh_size;
617 }
618 }
619 if (!info->symtab_start)
620 fatal("%s has no symtab?\n", filename);
621
622 /* Fix endianness in symbols */
623 for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
624 sym->st_shndx = TO_NATIVE(sym->st_shndx);
625 sym->st_name = TO_NATIVE(sym->st_name);
626 sym->st_value = TO_NATIVE(sym->st_value);
627 sym->st_size = TO_NATIVE(sym->st_size);
628 }
629
630 if (symtab_shndx_idx != ~0U) {
631 Elf32_Word *p;
632 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
633 fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
634 filename, sechdrs[symtab_shndx_idx].sh_link,
635 symtab_idx);
636 /* Fix endianness */
637 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
638 p++)
639 *p = TO_NATIVE(*p);
640 }
641
642 return 1;
643 }
644
645 static void parse_elf_finish(struct elf_info *info)
646 {
647 release_file(info->hdr, info->size);
648 }
649
650 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
651 {
652 /* ignore __this_module, it will be resolved shortly */
653 if (strcmp(symname, "__this_module") == 0)
654 return 1;
655 /* ignore global offset table */
656 if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
657 return 1;
658 if (info->hdr->e_machine == EM_PPC)
659 /* Special register function linked on all modules during final link of .ko */
660 if (strstarts(symname, "_restgpr_") ||
661 strstarts(symname, "_savegpr_") ||
662 strstarts(symname, "_rest32gpr_") ||
663 strstarts(symname, "_save32gpr_") ||
664 strstarts(symname, "_restvr_") ||
665 strstarts(symname, "_savevr_"))
666 return 1;
667 if (info->hdr->e_machine == EM_PPC64)
668 /* Special register function linked on all modules during final link of .ko */
669 if (strstarts(symname, "_restgpr0_") ||
670 strstarts(symname, "_savegpr0_") ||
671 strstarts(symname, "_restvr_") ||
672 strstarts(symname, "_savevr_") ||
673 strcmp(symname, ".TOC.") == 0)
674 return 1;
675 /* Do not ignore this symbol */
676 return 0;
677 }
678
679 static void handle_modversion(const struct module *mod,
680 const struct elf_info *info,
681 const Elf_Sym *sym, const char *symname)
682 {
683 unsigned int crc;
684
685 if (sym->st_shndx == SHN_UNDEF) {
686 warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
687 symname, mod->name, mod->is_vmlinux ? "" : ".ko");
688 return;
689 }
690
691 if (sym->st_shndx == SHN_ABS) {
692 crc = sym->st_value;
693 } else {
694 unsigned int *crcp;
695
696 /* symbol points to the CRC in the ELF object */
697 crcp = sym_get_data(info, sym);
698 crc = TO_NATIVE(*crcp);
699 }
700 sym_set_crc(symname, crc);
701 }
702
703 static void handle_symbol(struct module *mod, struct elf_info *info,
704 const Elf_Sym *sym, const char *symname)
705 {
706 enum export export;
707 const char *name;
708
709 if (strstarts(symname, "__ksymtab"))
710 export = export_from_secname(info, get_secindex(info, sym));
711 else
712 export = export_from_sec(info, get_secindex(info, sym));
713
714 switch (sym->st_shndx) {
715 case SHN_COMMON:
716 if (strstarts(symname, "__gnu_lto_")) {
717 /* Should warn here, but modpost runs before the linker */
718 } else
719 warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
720 break;
721 case SHN_UNDEF:
722 /* undefined symbol */
723 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
724 ELF_ST_BIND(sym->st_info) != STB_WEAK)
725 break;
726 if (ignore_undef_symbol(info, symname))
727 break;
728 if (info->hdr->e_machine == EM_SPARC ||
729 info->hdr->e_machine == EM_SPARCV9) {
730 /* Ignore register directives. */
731 if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
732 break;
733 if (symname[0] == '.') {
734 char *munged = NOFAIL(strdup(symname));
735 munged[0] = '_';
736 munged[1] = toupper(munged[1]);
737 symname = munged;
738 }
739 }
740
741 mod->unres = alloc_symbol(symname,
742 ELF_ST_BIND(sym->st_info) == STB_WEAK,
743 mod->unres);
744 break;
745 default:
746 /* All exported symbols */
747 if (strstarts(symname, "__ksymtab_")) {
748 name = symname + strlen("__ksymtab_");
749 sym_add_exported(name, mod, export);
750 }
751 if (strcmp(symname, "init_module") == 0)
752 mod->has_init = 1;
753 if (strcmp(symname, "cleanup_module") == 0)
754 mod->has_cleanup = 1;
755 break;
756 }
757 }
758
759 /**
760 * Parse tag=value strings from .modinfo section
761 **/
762 static char *next_string(char *string, unsigned long *secsize)
763 {
764 /* Skip non-zero chars */
765 while (string[0]) {
766 string++;
767 if ((*secsize)-- <= 1)
768 return NULL;
769 }
770
771 /* Skip any zero padding. */
772 while (!string[0]) {
773 string++;
774 if ((*secsize)-- <= 1)
775 return NULL;
776 }
777 return string;
778 }
779
780 static char *get_next_modinfo(struct elf_info *info, const char *tag,
781 char *prev)
782 {
783 char *p;
784 unsigned int taglen = strlen(tag);
785 char *modinfo = info->modinfo;
786 unsigned long size = info->modinfo_len;
787
788 if (prev) {
789 size -= prev - modinfo;
790 modinfo = next_string(prev, &size);
791 }
792
793 for (p = modinfo; p; p = next_string(p, &size)) {
794 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
795 return p + taglen + 1;
796 }
797 return NULL;
798 }
799
800 static char *get_modinfo(struct elf_info *info, const char *tag)
801
802 {
803 return get_next_modinfo(info, tag, NULL);
804 }
805
806 /**
807 * Test if string s ends in string sub
808 * return 0 if match
809 **/
810 static int strrcmp(const char *s, const char *sub)
811 {
812 int slen, sublen;
813
814 if (!s || !sub)
815 return 1;
816
817 slen = strlen(s);
818 sublen = strlen(sub);
819
820 if ((slen == 0) || (sublen == 0))
821 return 1;
822
823 if (sublen > slen)
824 return 1;
825
826 return memcmp(s + slen - sublen, sub, sublen);
827 }
828
829 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
830 {
831 if (sym)
832 return elf->strtab + sym->st_name;
833 else
834 return "(unknown)";
835 }
836
837 /* The pattern is an array of simple patterns.
838 * "foo" will match an exact string equal to "foo"
839 * "*foo" will match a string that ends with "foo"
840 * "foo*" will match a string that begins with "foo"
841 * "*foo*" will match a string that contains "foo"
842 */
843 static int match(const char *sym, const char * const pat[])
844 {
845 const char *p;
846 while (*pat) {
847 p = *pat++;
848 const char *endp = p + strlen(p) - 1;
849
850 /* "*foo*" */
851 if (*p == '*' && *endp == '*') {
852 char *bare = NOFAIL(strndup(p + 1, strlen(p) - 2));
853 char *here = strstr(sym, bare);
854
855 free(bare);
856 if (here != NULL)
857 return 1;
858 }
859 /* "*foo" */
860 else if (*p == '*') {
861 if (strrcmp(sym, p + 1) == 0)
862 return 1;
863 }
864 /* "foo*" */
865 else if (*endp == '*') {
866 if (strncmp(sym, p, strlen(p) - 1) == 0)
867 return 1;
868 }
869 /* no wildcards */
870 else {
871 if (strcmp(p, sym) == 0)
872 return 1;
873 }
874 }
875 /* no match */
876 return 0;
877 }
878
879 /* sections that we do not want to do full section mismatch check on */
880 static const char *const section_white_list[] =
881 {
882 ".comment*",
883 ".debug*",
884 ".cranges", /* sh64 */
885 ".zdebug*", /* Compressed debug sections. */
886 ".GCC.command.line", /* record-gcc-switches */
887 ".mdebug*", /* alpha, score, mips etc. */
888 ".pdr", /* alpha, score, mips etc. */
889 ".stab*",
890 ".note*",
891 ".got*",
892 ".toc*",
893 ".xt.prop", /* xtensa */
894 ".xt.lit", /* xtensa */
895 ".arcextmap*", /* arc */
896 ".gnu.linkonce.arcext*", /* arc : modules */
897 ".cmem*", /* EZchip */
898 ".fmt_slot*", /* EZchip */
899 ".gnu.lto*",
900 ".discard.*",
901 NULL
902 };
903
904 /*
905 * This is used to find sections missing the SHF_ALLOC flag.
906 * The cause of this is often a section specified in assembler
907 * without "ax" / "aw".
908 */
909 static void check_section(const char *modname, struct elf_info *elf,
910 Elf_Shdr *sechdr)
911 {
912 const char *sec = sech_name(elf, sechdr);
913
914 if (sechdr->sh_type == SHT_PROGBITS &&
915 !(sechdr->sh_flags & SHF_ALLOC) &&
916 !match(sec, section_white_list)) {
917 warn("%s (%s): unexpected non-allocatable section.\n"
918 "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
919 "Note that for example <linux/init.h> contains\n"
920 "section definitions for use in .S files.\n\n",
921 modname, sec);
922 }
923 }
924
925
926
927 #define ALL_INIT_DATA_SECTIONS \
928 ".init.setup", ".init.rodata", ".meminit.rodata", \
929 ".init.data", ".meminit.data"
930 #define ALL_EXIT_DATA_SECTIONS \
931 ".exit.data", ".memexit.data"
932
933 #define ALL_INIT_TEXT_SECTIONS \
934 ".init.text", ".meminit.text"
935 #define ALL_EXIT_TEXT_SECTIONS \
936 ".exit.text", ".memexit.text"
937
938 #define ALL_PCI_INIT_SECTIONS \
939 ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
940 ".pci_fixup_enable", ".pci_fixup_resume", \
941 ".pci_fixup_resume_early", ".pci_fixup_suspend"
942
943 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
944 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
945
946 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
947 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
948
949 #define DATA_SECTIONS ".data", ".data.rel"
950 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
951 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
952 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
953 ".fixup", ".entry.text", ".exception.text", ".text.*", \
954 ".coldtext"
955
956 #define INIT_SECTIONS ".init.*"
957 #define MEM_INIT_SECTIONS ".meminit.*"
958
959 #define EXIT_SECTIONS ".exit.*"
960 #define MEM_EXIT_SECTIONS ".memexit.*"
961
962 #define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
963 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
964
965 /* init data sections */
966 static const char *const init_data_sections[] =
967 { ALL_INIT_DATA_SECTIONS, NULL };
968
969 /* all init sections */
970 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
971
972 /* All init and exit sections (code + data) */
973 static const char *const init_exit_sections[] =
974 {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
975
976 /* all text sections */
977 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
978
979 /* data section */
980 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
981
982
983 /* symbols in .data that may refer to init/exit sections */
984 #define DEFAULT_SYMBOL_WHITE_LIST \
985 "*driver", \
986 "*_template", /* scsi uses *_template a lot */ \
987 "*_timer", /* arm uses ops structures named _timer a lot */ \
988 "*_sht", /* scsi also used *_sht to some extent */ \
989 "*_ops", \
990 "*_probe", \
991 "*_probe_one", \
992 "*_console"
993
994 static const char *const head_sections[] = { ".head.text*", NULL };
995 static const char *const linker_symbols[] =
996 { "__init_begin", "_sinittext", "_einittext", NULL };
997 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
998
999 enum mismatch {
1000 TEXT_TO_ANY_INIT,
1001 DATA_TO_ANY_INIT,
1002 TEXT_TO_ANY_EXIT,
1003 DATA_TO_ANY_EXIT,
1004 XXXINIT_TO_SOME_INIT,
1005 XXXEXIT_TO_SOME_EXIT,
1006 ANY_INIT_TO_ANY_EXIT,
1007 ANY_EXIT_TO_ANY_INIT,
1008 EXPORT_TO_INIT_EXIT,
1009 EXTABLE_TO_NON_TEXT,
1010 };
1011
1012 /**
1013 * Describe how to match sections on different criterias:
1014 *
1015 * @fromsec: Array of sections to be matched.
1016 *
1017 * @bad_tosec: Relocations applied to a section in @fromsec to a section in
1018 * this array is forbidden (black-list). Can be empty.
1019 *
1020 * @good_tosec: Relocations applied to a section in @fromsec must be
1021 * targetting sections in this array (white-list). Can be empty.
1022 *
1023 * @mismatch: Type of mismatch.
1024 *
1025 * @symbol_white_list: Do not match a relocation to a symbol in this list
1026 * even if it is targetting a section in @bad_to_sec.
1027 *
1028 * @handler: Specific handler to call when a match is found. If NULL,
1029 * default_mismatch_handler() will be called.
1030 *
1031 */
1032 struct sectioncheck {
1033 const char *fromsec[20];
1034 const char *bad_tosec[20];
1035 const char *good_tosec[20];
1036 enum mismatch mismatch;
1037 const char *symbol_white_list[20];
1038 void (*handler)(const char *modname, struct elf_info *elf,
1039 const struct sectioncheck* const mismatch,
1040 Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
1041
1042 };
1043
1044 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
1045 const struct sectioncheck* const mismatch,
1046 Elf_Rela *r, Elf_Sym *sym,
1047 const char *fromsec);
1048
1049 static const struct sectioncheck sectioncheck[] = {
1050 /* Do not reference init/exit code/data from
1051 * normal code and data
1052 */
1053 {
1054 .fromsec = { TEXT_SECTIONS, NULL },
1055 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1056 .mismatch = TEXT_TO_ANY_INIT,
1057 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1058 },
1059 {
1060 .fromsec = { DATA_SECTIONS, NULL },
1061 .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1062 .mismatch = DATA_TO_ANY_INIT,
1063 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1064 },
1065 {
1066 .fromsec = { DATA_SECTIONS, NULL },
1067 .bad_tosec = { INIT_SECTIONS, NULL },
1068 .mismatch = DATA_TO_ANY_INIT,
1069 .symbol_white_list = {
1070 "*_template", "*_timer", "*_sht", "*_ops",
1071 "*_probe", "*_probe_one", "*_console", NULL
1072 },
1073 },
1074 {
1075 .fromsec = { TEXT_SECTIONS, NULL },
1076 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1077 .mismatch = TEXT_TO_ANY_EXIT,
1078 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1079 },
1080 {
1081 .fromsec = { DATA_SECTIONS, NULL },
1082 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1083 .mismatch = DATA_TO_ANY_EXIT,
1084 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1085 },
1086 /* Do not reference init code/data from meminit code/data */
1087 {
1088 .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1089 .bad_tosec = { INIT_SECTIONS, NULL },
1090 .mismatch = XXXINIT_TO_SOME_INIT,
1091 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1092 },
1093 /* Do not reference exit code/data from memexit code/data */
1094 {
1095 .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1096 .bad_tosec = { EXIT_SECTIONS, NULL },
1097 .mismatch = XXXEXIT_TO_SOME_EXIT,
1098 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1099 },
1100 /* Do not use exit code/data from init code */
1101 {
1102 .fromsec = { ALL_INIT_SECTIONS, NULL },
1103 .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1104 .mismatch = ANY_INIT_TO_ANY_EXIT,
1105 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1106 },
1107 /* Do not use init code/data from exit code */
1108 {
1109 .fromsec = { ALL_EXIT_SECTIONS, NULL },
1110 .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1111 .mismatch = ANY_EXIT_TO_ANY_INIT,
1112 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1113 },
1114 {
1115 .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1116 .bad_tosec = { INIT_SECTIONS, NULL },
1117 .mismatch = ANY_INIT_TO_ANY_EXIT,
1118 .symbol_white_list = { NULL },
1119 },
1120 /* Do not export init/exit functions or data */
1121 {
1122 .fromsec = { "__ksymtab*", NULL },
1123 .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1124 .mismatch = EXPORT_TO_INIT_EXIT,
1125 .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1126 },
1127 {
1128 .fromsec = { "__ex_table", NULL },
1129 /* If you're adding any new black-listed sections in here, consider
1130 * adding a special 'printer' for them in scripts/check_extable.
1131 */
1132 .bad_tosec = { ".altinstr_replacement", NULL },
1133 .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1134 .mismatch = EXTABLE_TO_NON_TEXT,
1135 .handler = extable_mismatch_handler,
1136 }
1137 };
1138
1139 static const struct sectioncheck *section_mismatch(
1140 const char *fromsec, const char *tosec)
1141 {
1142 int i;
1143 int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1144 const struct sectioncheck *check = &sectioncheck[0];
1145
1146 /*
1147 * The target section could be the SHT_NUL section when we're
1148 * handling relocations to un-resolved symbols, trying to match it
1149 * doesn't make much sense and causes build failures on parisc
1150 * architectures.
1151 */
1152 if (*tosec == '\0')
1153 return NULL;
1154
1155 for (i = 0; i < elems; i++) {
1156 if (match(fromsec, check->fromsec)) {
1157 if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1158 return check;
1159 if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1160 return check;
1161 }
1162 check++;
1163 }
1164 return NULL;
1165 }
1166
1167 /**
1168 * Whitelist to allow certain references to pass with no warning.
1169 *
1170 * Pattern 1:
1171 * If a module parameter is declared __initdata and permissions=0
1172 * then this is legal despite the warning generated.
1173 * We cannot see value of permissions here, so just ignore
1174 * this pattern.
1175 * The pattern is identified by:
1176 * tosec = .init.data
1177 * fromsec = .data*
1178 * atsym =__param*
1179 *
1180 * Pattern 1a:
1181 * module_param_call() ops can refer to __init set function if permissions=0
1182 * The pattern is identified by:
1183 * tosec = .init.text
1184 * fromsec = .data*
1185 * atsym = __param_ops_*
1186 *
1187 * Pattern 2:
1188 * Many drivers utilise a *driver container with references to
1189 * add, remove, probe functions etc.
1190 * the pattern is identified by:
1191 * tosec = init or exit section
1192 * fromsec = data section
1193 * atsym = *driver, *_template, *_sht, *_ops, *_probe,
1194 * *probe_one, *_console, *_timer
1195 *
1196 * Pattern 3:
1197 * Whitelist all references from .head.text to any init section
1198 *
1199 * Pattern 4:
1200 * Some symbols belong to init section but still it is ok to reference
1201 * these from non-init sections as these symbols don't have any memory
1202 * allocated for them and symbol address and value are same. So even
1203 * if init section is freed, its ok to reference those symbols.
1204 * For ex. symbols marking the init section boundaries.
1205 * This pattern is identified by
1206 * refsymname = __init_begin, _sinittext, _einittext
1207 *
1208 * Pattern 5:
1209 * GCC may optimize static inlines when fed constant arg(s) resulting
1210 * in functions like cpumask_empty() -- generating an associated symbol
1211 * cpumask_empty.constprop.3 that appears in the audit. If the const that
1212 * is passed in comes from __init, like say nmi_ipi_mask, we get a
1213 * meaningless section warning. May need to add isra symbols too...
1214 * This pattern is identified by
1215 * tosec = init section
1216 * fromsec = text section
1217 * refsymname = *.constprop.*
1218 *
1219 * Pattern 6:
1220 * Hide section mismatch warnings for ELF local symbols. The goal
1221 * is to eliminate false positive modpost warnings caused by
1222 * compiler-generated ELF local symbol names such as ".LANCHOR1".
1223 * Autogenerated symbol names bypass modpost's "Pattern 2"
1224 * whitelisting, which relies on pattern-matching against symbol
1225 * names to work. (One situation where gcc can autogenerate ELF
1226 * local symbols is when "-fsection-anchors" is used.)
1227 **/
1228 static int secref_whitelist(const struct sectioncheck *mismatch,
1229 const char *fromsec, const char *fromsym,
1230 const char *tosec, const char *tosym)
1231 {
1232 /* Check for pattern 1 */
1233 if (match(tosec, init_data_sections) &&
1234 match(fromsec, data_sections) &&
1235 strstarts(fromsym, "__param"))
1236 return 0;
1237
1238 /* Check for pattern 1a */
1239 if (strcmp(tosec, ".init.text") == 0 &&
1240 match(fromsec, data_sections) &&
1241 strstarts(fromsym, "__param_ops_"))
1242 return 0;
1243
1244 /* Check for pattern 2 */
1245 if (match(tosec, init_exit_sections) &&
1246 match(fromsec, data_sections) &&
1247 match(fromsym, mismatch->symbol_white_list))
1248 return 0;
1249
1250 /* Check for pattern 3 */
1251 if (match(fromsec, head_sections) &&
1252 match(tosec, init_sections))
1253 return 0;
1254
1255 /* Check for pattern 4 */
1256 if (match(tosym, linker_symbols))
1257 return 0;
1258
1259 /* Check for pattern 5 */
1260 if (match(fromsec, text_sections) &&
1261 match(tosec, init_sections) &&
1262 match(fromsym, optim_symbols))
1263 return 0;
1264
1265 /* Check for pattern 6 */
1266 if (strstarts(fromsym, ".L"))
1267 return 0;
1268
1269 return 1;
1270 }
1271
1272 static inline int is_arm_mapping_symbol(const char *str)
1273 {
1274 return str[0] == '$' && strchr("axtd", str[1])
1275 && (str[2] == '\0' || str[2] == '.');
1276 }
1277
1278 /*
1279 * If there's no name there, ignore it; likewise, ignore it if it's
1280 * one of the magic symbols emitted used by current ARM tools.
1281 *
1282 * Otherwise if find_symbols_between() returns those symbols, they'll
1283 * fail the whitelist tests and cause lots of false alarms ... fixable
1284 * only by merging __exit and __init sections into __text, bloating
1285 * the kernel (which is especially evil on embedded platforms).
1286 */
1287 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1288 {
1289 const char *name = elf->strtab + sym->st_name;
1290
1291 if (!name || !strlen(name))
1292 return 0;
1293 return !is_arm_mapping_symbol(name);
1294 }
1295
1296 /**
1297 * Find symbol based on relocation record info.
1298 * In some cases the symbol supplied is a valid symbol so
1299 * return refsym. If st_name != 0 we assume this is a valid symbol.
1300 * In other cases the symbol needs to be looked up in the symbol table
1301 * based on section and address.
1302 * **/
1303 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1304 Elf_Sym *relsym)
1305 {
1306 Elf_Sym *sym;
1307 Elf_Sym *near = NULL;
1308 Elf64_Sword distance = 20;
1309 Elf64_Sword d;
1310 unsigned int relsym_secindex;
1311
1312 if (relsym->st_name != 0)
1313 return relsym;
1314
1315 relsym_secindex = get_secindex(elf, relsym);
1316 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1317 if (get_secindex(elf, sym) != relsym_secindex)
1318 continue;
1319 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1320 continue;
1321 if (!is_valid_name(elf, sym))
1322 continue;
1323 if (sym->st_value == addr)
1324 return sym;
1325 /* Find a symbol nearby - addr are maybe negative */
1326 d = sym->st_value - addr;
1327 if (d < 0)
1328 d = addr - sym->st_value;
1329 if (d < distance) {
1330 distance = d;
1331 near = sym;
1332 }
1333 }
1334 /* We need a close match */
1335 if (distance < 20)
1336 return near;
1337 else
1338 return NULL;
1339 }
1340
1341 /*
1342 * Find symbols before or equal addr and after addr - in the section sec.
1343 * If we find two symbols with equal offset prefer one with a valid name.
1344 * The ELF format may have a better way to detect what type of symbol
1345 * it is, but this works for now.
1346 **/
1347 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1348 const char *sec)
1349 {
1350 Elf_Sym *sym;
1351 Elf_Sym *near = NULL;
1352 Elf_Addr distance = ~0;
1353
1354 for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1355 const char *symsec;
1356
1357 if (is_shndx_special(sym->st_shndx))
1358 continue;
1359 symsec = sec_name(elf, get_secindex(elf, sym));
1360 if (strcmp(symsec, sec) != 0)
1361 continue;
1362 if (!is_valid_name(elf, sym))
1363 continue;
1364 if (sym->st_value <= addr) {
1365 if ((addr - sym->st_value) < distance) {
1366 distance = addr - sym->st_value;
1367 near = sym;
1368 } else if ((addr - sym->st_value) == distance) {
1369 near = sym;
1370 }
1371 }
1372 }
1373 return near;
1374 }
1375
1376 /*
1377 * Convert a section name to the function/data attribute
1378 * .init.text => __init
1379 * .memexitconst => __memconst
1380 * etc.
1381 *
1382 * The memory of returned value has been allocated on a heap. The user of this
1383 * method should free it after usage.
1384 */
1385 static char *sec2annotation(const char *s)
1386 {
1387 if (match(s, init_exit_sections)) {
1388 char *p = NOFAIL(malloc(20));
1389 char *r = p;
1390
1391 *p++ = '_';
1392 *p++ = '_';
1393 if (*s == '.')
1394 s++;
1395 while (*s && *s != '.')
1396 *p++ = *s++;
1397 *p = '\0';
1398 if (*s == '.')
1399 s++;
1400 if (strstr(s, "rodata") != NULL)
1401 strcat(p, "const ");
1402 else if (strstr(s, "data") != NULL)
1403 strcat(p, "data ");
1404 else
1405 strcat(p, " ");
1406 return r;
1407 } else {
1408 return NOFAIL(strdup(""));
1409 }
1410 }
1411
1412 static int is_function(Elf_Sym *sym)
1413 {
1414 if (sym)
1415 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1416 else
1417 return -1;
1418 }
1419
1420 static void print_section_list(const char * const list[20])
1421 {
1422 const char *const *s = list;
1423
1424 while (*s) {
1425 fprintf(stderr, "%s", *s);
1426 s++;
1427 if (*s)
1428 fprintf(stderr, ", ");
1429 }
1430 fprintf(stderr, "\n");
1431 }
1432
1433 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1434 {
1435 switch (is_func) {
1436 case 0: *name = "variable"; *name_p = ""; break;
1437 case 1: *name = "function"; *name_p = "()"; break;
1438 default: *name = "(unknown reference)"; *name_p = ""; break;
1439 }
1440 }
1441
1442 /*
1443 * Print a warning about a section mismatch.
1444 * Try to find symbols near it so user can find it.
1445 * Check whitelist before warning - it may be a false positive.
1446 */
1447 static void report_sec_mismatch(const char *modname,
1448 const struct sectioncheck *mismatch,
1449 const char *fromsec,
1450 unsigned long long fromaddr,
1451 const char *fromsym,
1452 int from_is_func,
1453 const char *tosec, const char *tosym,
1454 int to_is_func)
1455 {
1456 const char *from, *from_p;
1457 const char *to, *to_p;
1458 char *prl_from;
1459 char *prl_to;
1460
1461 sec_mismatch_count++;
1462
1463 get_pretty_name(from_is_func, &from, &from_p);
1464 get_pretty_name(to_is_func, &to, &to_p);
1465
1466 warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1467 "to the %s %s:%s%s\n",
1468 modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1469 tosym, to_p);
1470
1471 switch (mismatch->mismatch) {
1472 case TEXT_TO_ANY_INIT:
1473 prl_from = sec2annotation(fromsec);
1474 prl_to = sec2annotation(tosec);
1475 fprintf(stderr,
1476 "The function %s%s() references\n"
1477 "the %s %s%s%s.\n"
1478 "This is often because %s lacks a %s\n"
1479 "annotation or the annotation of %s is wrong.\n",
1480 prl_from, fromsym,
1481 to, prl_to, tosym, to_p,
1482 fromsym, prl_to, tosym);
1483 free(prl_from);
1484 free(prl_to);
1485 break;
1486 case DATA_TO_ANY_INIT: {
1487 prl_to = sec2annotation(tosec);
1488 fprintf(stderr,
1489 "The variable %s references\n"
1490 "the %s %s%s%s\n"
1491 "If the reference is valid then annotate the\n"
1492 "variable with __init* or __refdata (see linux/init.h) "
1493 "or name the variable:\n",
1494 fromsym, to, prl_to, tosym, to_p);
1495 print_section_list(mismatch->symbol_white_list);
1496 free(prl_to);
1497 break;
1498 }
1499 case TEXT_TO_ANY_EXIT:
1500 prl_to = sec2annotation(tosec);
1501 fprintf(stderr,
1502 "The function %s() references a %s in an exit section.\n"
1503 "Often the %s %s%s has valid usage outside the exit section\n"
1504 "and the fix is to remove the %sannotation of %s.\n",
1505 fromsym, to, to, tosym, to_p, prl_to, tosym);
1506 free(prl_to);
1507 break;
1508 case DATA_TO_ANY_EXIT: {
1509 prl_to = sec2annotation(tosec);
1510 fprintf(stderr,
1511 "The variable %s references\n"
1512 "the %s %s%s%s\n"
1513 "If the reference is valid then annotate the\n"
1514 "variable with __exit* (see linux/init.h) or "
1515 "name the variable:\n",
1516 fromsym, to, prl_to, tosym, to_p);
1517 print_section_list(mismatch->symbol_white_list);
1518 free(prl_to);
1519 break;
1520 }
1521 case XXXINIT_TO_SOME_INIT:
1522 case XXXEXIT_TO_SOME_EXIT:
1523 prl_from = sec2annotation(fromsec);
1524 prl_to = sec2annotation(tosec);
1525 fprintf(stderr,
1526 "The %s %s%s%s references\n"
1527 "a %s %s%s%s.\n"
1528 "If %s is only used by %s then\n"
1529 "annotate %s with a matching annotation.\n",
1530 from, prl_from, fromsym, from_p,
1531 to, prl_to, tosym, to_p,
1532 tosym, fromsym, tosym);
1533 free(prl_from);
1534 free(prl_to);
1535 break;
1536 case ANY_INIT_TO_ANY_EXIT:
1537 prl_from = sec2annotation(fromsec);
1538 prl_to = sec2annotation(tosec);
1539 fprintf(stderr,
1540 "The %s %s%s%s references\n"
1541 "a %s %s%s%s.\n"
1542 "This is often seen when error handling "
1543 "in the init function\n"
1544 "uses functionality in the exit path.\n"
1545 "The fix is often to remove the %sannotation of\n"
1546 "%s%s so it may be used outside an exit section.\n",
1547 from, prl_from, fromsym, from_p,
1548 to, prl_to, tosym, to_p,
1549 prl_to, tosym, to_p);
1550 free(prl_from);
1551 free(prl_to);
1552 break;
1553 case ANY_EXIT_TO_ANY_INIT:
1554 prl_from = sec2annotation(fromsec);
1555 prl_to = sec2annotation(tosec);
1556 fprintf(stderr,
1557 "The %s %s%s%s references\n"
1558 "a %s %s%s%s.\n"
1559 "This is often seen when error handling "
1560 "in the exit function\n"
1561 "uses functionality in the init path.\n"
1562 "The fix is often to remove the %sannotation of\n"
1563 "%s%s so it may be used outside an init section.\n",
1564 from, prl_from, fromsym, from_p,
1565 to, prl_to, tosym, to_p,
1566 prl_to, tosym, to_p);
1567 free(prl_from);
1568 free(prl_to);
1569 break;
1570 case EXPORT_TO_INIT_EXIT:
1571 prl_to = sec2annotation(tosec);
1572 fprintf(stderr,
1573 "The symbol %s is exported and annotated %s\n"
1574 "Fix this by removing the %sannotation of %s "
1575 "or drop the export.\n",
1576 tosym, prl_to, prl_to, tosym);
1577 free(prl_to);
1578 break;
1579 case EXTABLE_TO_NON_TEXT:
1580 fatal("There's a special handler for this mismatch type, "
1581 "we should never get here.");
1582 break;
1583 }
1584 fprintf(stderr, "\n");
1585 }
1586
1587 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1588 const struct sectioncheck* const mismatch,
1589 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1590 {
1591 const char *tosec;
1592 Elf_Sym *to;
1593 Elf_Sym *from;
1594 const char *tosym;
1595 const char *fromsym;
1596
1597 from = find_elf_symbol2(elf, r->r_offset, fromsec);
1598 fromsym = sym_name(elf, from);
1599
1600 if (strstarts(fromsym, "reference___initcall"))
1601 return;
1602
1603 tosec = sec_name(elf, get_secindex(elf, sym));
1604 to = find_elf_symbol(elf, r->r_addend, sym);
1605 tosym = sym_name(elf, to);
1606
1607 /* check whitelist - we may ignore it */
1608 if (secref_whitelist(mismatch,
1609 fromsec, fromsym, tosec, tosym)) {
1610 report_sec_mismatch(modname, mismatch,
1611 fromsec, r->r_offset, fromsym,
1612 is_function(from), tosec, tosym,
1613 is_function(to));
1614 }
1615 }
1616
1617 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1618 {
1619 if (section_index > elf->num_sections)
1620 fatal("section_index is outside elf->num_sections!\n");
1621
1622 return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1623 }
1624
1625 /*
1626 * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1627 * to know the sizeof(struct exception_table_entry) for the target architecture.
1628 */
1629 static unsigned int extable_entry_size = 0;
1630 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1631 {
1632 /*
1633 * If we're currently checking the second relocation within __ex_table,
1634 * that relocation offset tells us the offsetof(struct
1635 * exception_table_entry, fixup) which is equal to sizeof(struct
1636 * exception_table_entry) divided by two. We use that to our advantage
1637 * since there's no portable way to get that size as every architecture
1638 * seems to go with different sized types. Not pretty but better than
1639 * hard-coding the size for every architecture..
1640 */
1641 if (!extable_entry_size)
1642 extable_entry_size = r->r_offset * 2;
1643 }
1644
1645 static inline bool is_extable_fault_address(Elf_Rela *r)
1646 {
1647 /*
1648 * extable_entry_size is only discovered after we've handled the
1649 * _second_ relocation in __ex_table, so only abort when we're not
1650 * handling the first reloc and extable_entry_size is zero.
1651 */
1652 if (r->r_offset && extable_entry_size == 0)
1653 fatal("extable_entry size hasn't been discovered!\n");
1654
1655 return ((r->r_offset == 0) ||
1656 (r->r_offset % extable_entry_size == 0));
1657 }
1658
1659 #define is_second_extable_reloc(Start, Cur, Sec) \
1660 (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1661
1662 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1663 const struct sectioncheck* const mismatch,
1664 Elf_Rela* r, Elf_Sym* sym,
1665 const char* fromsec, const char* tosec)
1666 {
1667 Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1668 const char* fromsym_name = sym_name(elf, fromsym);
1669 Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1670 const char* tosym_name = sym_name(elf, tosym);
1671 const char* from_pretty_name;
1672 const char* from_pretty_name_p;
1673 const char* to_pretty_name;
1674 const char* to_pretty_name_p;
1675
1676 get_pretty_name(is_function(fromsym),
1677 &from_pretty_name, &from_pretty_name_p);
1678 get_pretty_name(is_function(tosym),
1679 &to_pretty_name, &to_pretty_name_p);
1680
1681 warn("%s(%s+0x%lx): Section mismatch in reference"
1682 " from the %s %s%s to the %s %s:%s%s\n",
1683 modname, fromsec, (long)r->r_offset, from_pretty_name,
1684 fromsym_name, from_pretty_name_p,
1685 to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1686
1687 if (!match(tosec, mismatch->bad_tosec) &&
1688 is_executable_section(elf, get_secindex(elf, sym)))
1689 fprintf(stderr,
1690 "The relocation at %s+0x%lx references\n"
1691 "section \"%s\" which is not in the list of\n"
1692 "authorized sections. If you're adding a new section\n"
1693 "and/or if this reference is valid, add \"%s\" to the\n"
1694 "list of authorized sections to jump to on fault.\n"
1695 "This can be achieved by adding \"%s\" to \n"
1696 "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1697 fromsec, (long)r->r_offset, tosec, tosec, tosec);
1698 }
1699
1700 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1701 const struct sectioncheck* const mismatch,
1702 Elf_Rela* r, Elf_Sym* sym,
1703 const char *fromsec)
1704 {
1705 const char* tosec = sec_name(elf, get_secindex(elf, sym));
1706
1707 sec_mismatch_count++;
1708
1709 report_extable_warnings(modname, elf, mismatch, r, sym, fromsec, tosec);
1710
1711 if (match(tosec, mismatch->bad_tosec))
1712 fatal("The relocation at %s+0x%lx references\n"
1713 "section \"%s\" which is black-listed.\n"
1714 "Something is seriously wrong and should be fixed.\n"
1715 "You might get more information about where this is\n"
1716 "coming from by using scripts/check_extable.sh %s\n",
1717 fromsec, (long)r->r_offset, tosec, modname);
1718 else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1719 if (is_extable_fault_address(r))
1720 fatal("The relocation at %s+0x%lx references\n"
1721 "section \"%s\" which is not executable, IOW\n"
1722 "it is not possible for the kernel to fault\n"
1723 "at that address. Something is seriously wrong\n"
1724 "and should be fixed.\n",
1725 fromsec, (long)r->r_offset, tosec);
1726 else
1727 fatal("The relocation at %s+0x%lx references\n"
1728 "section \"%s\" which is not executable, IOW\n"
1729 "the kernel will fault if it ever tries to\n"
1730 "jump to it. Something is seriously wrong\n"
1731 "and should be fixed.\n",
1732 fromsec, (long)r->r_offset, tosec);
1733 }
1734 }
1735
1736 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1737 Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1738 {
1739 const char *tosec = sec_name(elf, get_secindex(elf, sym));
1740 const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1741
1742 if (mismatch) {
1743 if (mismatch->handler)
1744 mismatch->handler(modname, elf, mismatch,
1745 r, sym, fromsec);
1746 else
1747 default_mismatch_handler(modname, elf, mismatch,
1748 r, sym, fromsec);
1749 }
1750 }
1751
1752 static unsigned int *reloc_location(struct elf_info *elf,
1753 Elf_Shdr *sechdr, Elf_Rela *r)
1754 {
1755 return sym_get_data_by_offset(elf, sechdr->sh_info, r->r_offset);
1756 }
1757
1758 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1759 {
1760 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1761 unsigned int *location = reloc_location(elf, sechdr, r);
1762
1763 switch (r_typ) {
1764 case R_386_32:
1765 r->r_addend = TO_NATIVE(*location);
1766 break;
1767 case R_386_PC32:
1768 r->r_addend = TO_NATIVE(*location) + 4;
1769 /* For CONFIG_RELOCATABLE=y */
1770 if (elf->hdr->e_type == ET_EXEC)
1771 r->r_addend += r->r_offset;
1772 break;
1773 }
1774 return 0;
1775 }
1776
1777 #ifndef R_ARM_CALL
1778 #define R_ARM_CALL 28
1779 #endif
1780 #ifndef R_ARM_JUMP24
1781 #define R_ARM_JUMP24 29
1782 #endif
1783
1784 #ifndef R_ARM_THM_CALL
1785 #define R_ARM_THM_CALL 10
1786 #endif
1787 #ifndef R_ARM_THM_JUMP24
1788 #define R_ARM_THM_JUMP24 30
1789 #endif
1790 #ifndef R_ARM_THM_JUMP19
1791 #define R_ARM_THM_JUMP19 51
1792 #endif
1793
1794 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1795 {
1796 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1797
1798 switch (r_typ) {
1799 case R_ARM_ABS32:
1800 /* From ARM ABI: (S + A) | T */
1801 r->r_addend = (int)(long)
1802 (elf->symtab_start + ELF_R_SYM(r->r_info));
1803 break;
1804 case R_ARM_PC24:
1805 case R_ARM_CALL:
1806 case R_ARM_JUMP24:
1807 case R_ARM_THM_CALL:
1808 case R_ARM_THM_JUMP24:
1809 case R_ARM_THM_JUMP19:
1810 /* From ARM ABI: ((S + A) | T) - P */
1811 r->r_addend = (int)(long)(elf->hdr +
1812 sechdr->sh_offset +
1813 (r->r_offset - sechdr->sh_addr));
1814 break;
1815 default:
1816 return 1;
1817 }
1818 return 0;
1819 }
1820
1821 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1822 {
1823 unsigned int r_typ = ELF_R_TYPE(r->r_info);
1824 unsigned int *location = reloc_location(elf, sechdr, r);
1825 unsigned int inst;
1826
1827 if (r_typ == R_MIPS_HI16)
1828 return 1; /* skip this */
1829 inst = TO_NATIVE(*location);
1830 switch (r_typ) {
1831 case R_MIPS_LO16:
1832 r->r_addend = inst & 0xffff;
1833 break;
1834 case R_MIPS_26:
1835 r->r_addend = (inst & 0x03ffffff) << 2;
1836 break;
1837 case R_MIPS_32:
1838 r->r_addend = inst;
1839 break;
1840 }
1841 return 0;
1842 }
1843
1844 static void section_rela(const char *modname, struct elf_info *elf,
1845 Elf_Shdr *sechdr)
1846 {
1847 Elf_Sym *sym;
1848 Elf_Rela *rela;
1849 Elf_Rela r;
1850 unsigned int r_sym;
1851 const char *fromsec;
1852
1853 Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1854 Elf_Rela *stop = (void *)start + sechdr->sh_size;
1855
1856 fromsec = sech_name(elf, sechdr);
1857 fromsec += strlen(".rela");
1858 /* if from section (name) is know good then skip it */
1859 if (match(fromsec, section_white_list))
1860 return;
1861
1862 for (rela = start; rela < stop; rela++) {
1863 r.r_offset = TO_NATIVE(rela->r_offset);
1864 #if KERNEL_ELFCLASS == ELFCLASS64
1865 if (elf->hdr->e_machine == EM_MIPS) {
1866 unsigned int r_typ;
1867 r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1868 r_sym = TO_NATIVE(r_sym);
1869 r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1870 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1871 } else {
1872 r.r_info = TO_NATIVE(rela->r_info);
1873 r_sym = ELF_R_SYM(r.r_info);
1874 }
1875 #else
1876 r.r_info = TO_NATIVE(rela->r_info);
1877 r_sym = ELF_R_SYM(r.r_info);
1878 #endif
1879 r.r_addend = TO_NATIVE(rela->r_addend);
1880 sym = elf->symtab_start + r_sym;
1881 /* Skip special sections */
1882 if (is_shndx_special(sym->st_shndx))
1883 continue;
1884 if (is_second_extable_reloc(start, rela, fromsec))
1885 find_extable_entry_size(fromsec, &r);
1886 check_section_mismatch(modname, elf, &r, sym, fromsec);
1887 }
1888 }
1889
1890 static void section_rel(const char *modname, struct elf_info *elf,
1891 Elf_Shdr *sechdr)
1892 {
1893 Elf_Sym *sym;
1894 Elf_Rel *rel;
1895 Elf_Rela r;
1896 unsigned int r_sym;
1897 const char *fromsec;
1898
1899 Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1900 Elf_Rel *stop = (void *)start + sechdr->sh_size;
1901
1902 fromsec = sech_name(elf, sechdr);
1903 fromsec += strlen(".rel");
1904 /* if from section (name) is know good then skip it */
1905 if (match(fromsec, section_white_list))
1906 return;
1907
1908 for (rel = start; rel < stop; rel++) {
1909 r.r_offset = TO_NATIVE(rel->r_offset);
1910 #if KERNEL_ELFCLASS == ELFCLASS64
1911 if (elf->hdr->e_machine == EM_MIPS) {
1912 unsigned int r_typ;
1913 r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1914 r_sym = TO_NATIVE(r_sym);
1915 r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1916 r.r_info = ELF64_R_INFO(r_sym, r_typ);
1917 } else {
1918 r.r_info = TO_NATIVE(rel->r_info);
1919 r_sym = ELF_R_SYM(r.r_info);
1920 }
1921 #else
1922 r.r_info = TO_NATIVE(rel->r_info);
1923 r_sym = ELF_R_SYM(r.r_info);
1924 #endif
1925 r.r_addend = 0;
1926 switch (elf->hdr->e_machine) {
1927 case EM_386:
1928 if (addend_386_rel(elf, sechdr, &r))
1929 continue;
1930 break;
1931 case EM_ARM:
1932 if (addend_arm_rel(elf, sechdr, &r))
1933 continue;
1934 break;
1935 case EM_MIPS:
1936 if (addend_mips_rel(elf, sechdr, &r))
1937 continue;
1938 break;
1939 }
1940 sym = elf->symtab_start + r_sym;
1941 /* Skip special sections */
1942 if (is_shndx_special(sym->st_shndx))
1943 continue;
1944 if (is_second_extable_reloc(start, rel, fromsec))
1945 find_extable_entry_size(fromsec, &r);
1946 check_section_mismatch(modname, elf, &r, sym, fromsec);
1947 }
1948 }
1949
1950 /**
1951 * A module includes a number of sections that are discarded
1952 * either when loaded or when used as built-in.
1953 * For loaded modules all functions marked __init and all data
1954 * marked __initdata will be discarded when the module has been initialized.
1955 * Likewise for modules used built-in the sections marked __exit
1956 * are discarded because __exit marked function are supposed to be called
1957 * only when a module is unloaded which never happens for built-in modules.
1958 * The check_sec_ref() function traverses all relocation records
1959 * to find all references to a section that reference a section that will
1960 * be discarded and warns about it.
1961 **/
1962 static void check_sec_ref(struct module *mod, const char *modname,
1963 struct elf_info *elf)
1964 {
1965 int i;
1966 Elf_Shdr *sechdrs = elf->sechdrs;
1967
1968 /* Walk through all sections */
1969 for (i = 0; i < elf->num_sections; i++) {
1970 check_section(modname, elf, &elf->sechdrs[i]);
1971 /* We want to process only relocation sections and not .init */
1972 if (sechdrs[i].sh_type == SHT_RELA)
1973 section_rela(modname, elf, &elf->sechdrs[i]);
1974 else if (sechdrs[i].sh_type == SHT_REL)
1975 section_rel(modname, elf, &elf->sechdrs[i]);
1976 }
1977 }
1978
1979 static char *remove_dot(char *s)
1980 {
1981 size_t n = strcspn(s, ".");
1982
1983 if (n && s[n]) {
1984 size_t m = strspn(s + n + 1, "0123456789");
1985 if (m && (s[n + m] == '.' || s[n + m] == 0))
1986 s[n] = 0;
1987 }
1988 return s;
1989 }
1990
1991 static void read_symbols(const char *modname)
1992 {
1993 const char *symname;
1994 char *version;
1995 char *license;
1996 char *namespace;
1997 struct module *mod;
1998 struct elf_info info = { };
1999 Elf_Sym *sym;
2000
2001 if (!parse_elf(&info, modname))
2002 return;
2003
2004 {
2005 char *tmp;
2006
2007 /* strip trailing .o */
2008 tmp = NOFAIL(strdup(modname));
2009 tmp[strlen(tmp) - 2] = '\0';
2010 mod = new_module(tmp);
2011 free(tmp);
2012 }
2013
2014 if (!mod->is_vmlinux) {
2015 license = get_modinfo(&info, "license");
2016 if (!license)
2017 warn("missing MODULE_LICENSE() in %s\n", modname);
2018 while (license) {
2019 if (license_is_gpl_compatible(license))
2020 mod->gpl_compatible = 1;
2021 else {
2022 mod->gpl_compatible = 0;
2023 break;
2024 }
2025 license = get_next_modinfo(&info, "license", license);
2026 }
2027
2028 namespace = get_modinfo(&info, "import_ns");
2029 while (namespace) {
2030 add_namespace(&mod->imported_namespaces, namespace);
2031 namespace = get_next_modinfo(&info, "import_ns",
2032 namespace);
2033 }
2034 }
2035
2036 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2037 symname = remove_dot(info.strtab + sym->st_name);
2038
2039 handle_symbol(mod, &info, sym, symname);
2040 handle_moddevtable(mod, &info, sym, symname);
2041 }
2042
2043 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2044 symname = remove_dot(info.strtab + sym->st_name);
2045
2046 /* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
2047 if (strstarts(symname, "__kstrtabns_"))
2048 sym_update_namespace(symname + strlen("__kstrtabns_"),
2049 namespace_from_kstrtabns(&info,
2050 sym));
2051
2052 if (strstarts(symname, "__crc_"))
2053 handle_modversion(mod, &info, sym,
2054 symname + strlen("__crc_"));
2055 }
2056
2057 // check for static EXPORT_SYMBOL_* functions && global vars
2058 for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
2059 unsigned char bind = ELF_ST_BIND(sym->st_info);
2060
2061 if (bind == STB_GLOBAL || bind == STB_WEAK) {
2062 struct symbol *s =
2063 find_symbol(remove_dot(info.strtab +
2064 sym->st_name));
2065
2066 if (s)
2067 s->is_static = 0;
2068 }
2069 }
2070
2071 check_sec_ref(mod, modname, &info);
2072
2073 if (!mod->is_vmlinux) {
2074 version = get_modinfo(&info, "version");
2075 if (version || all_versions)
2076 get_src_version(modname, mod->srcversion,
2077 sizeof(mod->srcversion) - 1);
2078 }
2079
2080 parse_elf_finish(&info);
2081
2082 /* Our trick to get versioning for module struct etc. - it's
2083 * never passed as an argument to an exported function, so
2084 * the automatic versioning doesn't pick it up, but it's really
2085 * important anyhow */
2086 if (modversions)
2087 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2088 }
2089
2090 static void read_symbols_from_files(const char *filename)
2091 {
2092 FILE *in = stdin;
2093 char fname[PATH_MAX];
2094
2095 if (strcmp(filename, "-") != 0) {
2096 in = fopen(filename, "r");
2097 if (!in)
2098 fatal("Can't open filenames file %s: %m", filename);
2099 }
2100
2101 while (fgets(fname, PATH_MAX, in) != NULL) {
2102 if (strends(fname, "\n"))
2103 fname[strlen(fname)-1] = '\0';
2104 read_symbols(fname);
2105 }
2106
2107 if (in != stdin)
2108 fclose(in);
2109 }
2110
2111 #define SZ 500
2112
2113 /* We first write the generated file into memory using the
2114 * following helper, then compare to the file on disk and
2115 * only update the later if anything changed */
2116
2117 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2118 const char *fmt, ...)
2119 {
2120 char tmp[SZ];
2121 int len;
2122 va_list ap;
2123
2124 va_start(ap, fmt);
2125 len = vsnprintf(tmp, SZ, fmt, ap);
2126 buf_write(buf, tmp, len);
2127 va_end(ap);
2128 }
2129
2130 void buf_write(struct buffer *buf, const char *s, int len)
2131 {
2132 if (buf->size - buf->pos < len) {
2133 buf->size += len + SZ;
2134 buf->p = NOFAIL(realloc(buf->p, buf->size));
2135 }
2136 strncpy(buf->p + buf->pos, s, len);
2137 buf->pos += len;
2138 }
2139
2140 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2141 {
2142 switch (exp) {
2143 case export_gpl:
2144 fatal("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
2145 m, s);
2146 break;
2147 case export_unused_gpl:
2148 fatal("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
2149 m, s);
2150 break;
2151 case export_gpl_future:
2152 warn("GPL-incompatible module %s.ko uses future GPL-only symbol '%s'\n",
2153 m, s);
2154 break;
2155 case export_plain:
2156 case export_unused:
2157 case export_unknown:
2158 /* ignore */
2159 break;
2160 }
2161 }
2162
2163 static void check_for_unused(enum export exp, const char *m, const char *s)
2164 {
2165 switch (exp) {
2166 case export_unused:
2167 case export_unused_gpl:
2168 warn("module %s.ko uses symbol '%s' marked UNUSED\n",
2169 m, s);
2170 break;
2171 default:
2172 /* ignore */
2173 break;
2174 }
2175 }
2176
2177 static int check_exports(struct module *mod)
2178 {
2179 struct symbol *s, *exp;
2180 int err = 0;
2181
2182 for (s = mod->unres; s; s = s->next) {
2183 const char *basename;
2184 exp = find_symbol(s->name);
2185 if (!exp || exp->module == mod) {
2186 if (have_vmlinux && !s->weak) {
2187 modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
2188 "\"%s\" [%s.ko] undefined!\n",
2189 s->name, mod->name);
2190 if (!warn_unresolved)
2191 err = 1;
2192 }
2193 continue;
2194 }
2195 basename = strrchr(mod->name, '/');
2196 if (basename)
2197 basename++;
2198 else
2199 basename = mod->name;
2200
2201 if (exp->namespace &&
2202 !module_imports_namespace(mod, exp->namespace)) {
2203 modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
2204 "module %s uses symbol %s from namespace %s, but does not import it.\n",
2205 basename, exp->name, exp->namespace);
2206 if (!allow_missing_ns_imports)
2207 err = 1;
2208 add_namespace(&mod->missing_namespaces, exp->namespace);
2209 }
2210
2211 if (!mod->gpl_compatible)
2212 check_for_gpl_usage(exp->export, basename, exp->name);
2213 check_for_unused(exp->export, basename, exp->name);
2214 }
2215
2216 return err;
2217 }
2218
2219 static int check_modname_len(struct module *mod)
2220 {
2221 const char *mod_name;
2222
2223 mod_name = strrchr(mod->name, '/');
2224 if (mod_name == NULL)
2225 mod_name = mod->name;
2226 else
2227 mod_name++;
2228 if (strlen(mod_name) >= MODULE_NAME_LEN) {
2229 merror("module name is too long [%s.ko]\n", mod->name);
2230 return 1;
2231 }
2232
2233 return 0;
2234 }
2235
2236 /**
2237 * Header for the generated file
2238 **/
2239 static void add_header(struct buffer *b, struct module *mod)
2240 {
2241 buf_printf(b, "#include <linux/module.h>\n");
2242 /*
2243 * Include build-salt.h after module.h in order to
2244 * inherit the definitions.
2245 */
2246 buf_printf(b, "#define INCLUDE_VERMAGIC\n");
2247 buf_printf(b, "#include <linux/build-salt.h>\n");
2248 buf_printf(b, "#include <linux/vermagic.h>\n");
2249 buf_printf(b, "#include <linux/compiler.h>\n");
2250 buf_printf(b, "\n");
2251 buf_printf(b, "BUILD_SALT;\n");
2252 buf_printf(b, "\n");
2253 buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2254 buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2255 buf_printf(b, "\n");
2256 buf_printf(b, "__visible struct module __this_module\n");
2257 buf_printf(b, "__section(\".gnu.linkonce.this_module\") = {\n");
2258 buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2259 if (mod->has_init)
2260 buf_printf(b, "\t.init = init_module,\n");
2261 if (mod->has_cleanup)
2262 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2263 "\t.exit = cleanup_module,\n"
2264 "#endif\n");
2265 buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2266 buf_printf(b, "};\n");
2267 }
2268
2269 static void add_intree_flag(struct buffer *b, int is_intree)
2270 {
2271 if (is_intree)
2272 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2273 }
2274
2275 /* Cannot check for assembler */
2276 static void add_retpoline(struct buffer *b)
2277 {
2278 buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2279 buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2280 buf_printf(b, "#endif\n");
2281 }
2282
2283 static void add_staging_flag(struct buffer *b, const char *name)
2284 {
2285 if (strstarts(name, "drivers/staging"))
2286 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2287 }
2288
2289 /**
2290 * Record CRCs for unresolved symbols
2291 **/
2292 static int add_versions(struct buffer *b, struct module *mod)
2293 {
2294 struct symbol *s, *exp;
2295 int err = 0;
2296
2297 for (s = mod->unres; s; s = s->next) {
2298 exp = find_symbol(s->name);
2299 if (!exp || exp->module == mod)
2300 continue;
2301 s->module = exp->module;
2302 s->crc_valid = exp->crc_valid;
2303 s->crc = exp->crc;
2304 }
2305
2306 if (!modversions)
2307 return err;
2308
2309 buf_printf(b, "\n");
2310 buf_printf(b, "static const struct modversion_info ____versions[]\n");
2311 buf_printf(b, "__used __section(\"__versions\") = {\n");
2312
2313 for (s = mod->unres; s; s = s->next) {
2314 if (!s->module)
2315 continue;
2316 if (!s->crc_valid) {
2317 warn("\"%s\" [%s.ko] has no CRC!\n",
2318 s->name, mod->name);
2319 continue;
2320 }
2321 if (strlen(s->name) >= MODULE_NAME_LEN) {
2322 merror("too long symbol \"%s\" [%s.ko]\n",
2323 s->name, mod->name);
2324 err = 1;
2325 break;
2326 }
2327 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2328 s->crc, s->name);
2329 }
2330
2331 buf_printf(b, "};\n");
2332
2333 return err;
2334 }
2335
2336 static void add_depends(struct buffer *b, struct module *mod)
2337 {
2338 struct symbol *s;
2339 int first = 1;
2340
2341 /* Clear ->seen flag of modules that own symbols needed by this. */
2342 for (s = mod->unres; s; s = s->next)
2343 if (s->module)
2344 s->module->seen = s->module->is_vmlinux;
2345
2346 buf_printf(b, "\n");
2347 buf_printf(b, "MODULE_INFO(depends, \"");
2348 for (s = mod->unres; s; s = s->next) {
2349 const char *p;
2350 if (!s->module)
2351 continue;
2352
2353 if (s->module->seen)
2354 continue;
2355
2356 s->module->seen = 1;
2357 p = strrchr(s->module->name, '/');
2358 if (p)
2359 p++;
2360 else
2361 p = s->module->name;
2362 buf_printf(b, "%s%s", first ? "" : ",", p);
2363 first = 0;
2364 }
2365 buf_printf(b, "\");\n");
2366 }
2367
2368 static void add_srcversion(struct buffer *b, struct module *mod)
2369 {
2370 if (mod->srcversion[0]) {
2371 buf_printf(b, "\n");
2372 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2373 mod->srcversion);
2374 }
2375 }
2376
2377 static void write_buf(struct buffer *b, const char *fname)
2378 {
2379 FILE *file;
2380
2381 file = fopen(fname, "w");
2382 if (!file) {
2383 perror(fname);
2384 exit(1);
2385 }
2386 if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2387 perror(fname);
2388 exit(1);
2389 }
2390 if (fclose(file) != 0) {
2391 perror(fname);
2392 exit(1);
2393 }
2394 }
2395
2396 static void write_if_changed(struct buffer *b, const char *fname)
2397 {
2398 char *tmp;
2399 FILE *file;
2400 struct stat st;
2401
2402 file = fopen(fname, "r");
2403 if (!file)
2404 goto write;
2405
2406 if (fstat(fileno(file), &st) < 0)
2407 goto close_write;
2408
2409 if (st.st_size != b->pos)
2410 goto close_write;
2411
2412 tmp = NOFAIL(malloc(b->pos));
2413 if (fread(tmp, 1, b->pos, file) != b->pos)
2414 goto free_write;
2415
2416 if (memcmp(tmp, b->p, b->pos) != 0)
2417 goto free_write;
2418
2419 free(tmp);
2420 fclose(file);
2421 return;
2422
2423 free_write:
2424 free(tmp);
2425 close_write:
2426 fclose(file);
2427 write:
2428 write_buf(b, fname);
2429 }
2430
2431 /* parse Module.symvers file. line format:
2432 * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
2433 **/
2434 static void read_dump(const char *fname)
2435 {
2436 char *buf, *pos, *line;
2437
2438 buf = read_text_file(fname);
2439 if (!buf)
2440 /* No symbol versions, silently ignore */
2441 return;
2442
2443 pos = buf;
2444
2445 while ((line = get_line(&pos))) {
2446 char *symname, *namespace, *modname, *d, *export;
2447 unsigned int crc;
2448 struct module *mod;
2449 struct symbol *s;
2450
2451 if (!(symname = strchr(line, '\t')))
2452 goto fail;
2453 *symname++ = '\0';
2454 if (!(modname = strchr(symname, '\t')))
2455 goto fail;
2456 *modname++ = '\0';
2457 if (!(export = strchr(modname, '\t')))
2458 goto fail;
2459 *export++ = '\0';
2460 if (!(namespace = strchr(export, '\t')))
2461 goto fail;
2462 *namespace++ = '\0';
2463
2464 crc = strtoul(line, &d, 16);
2465 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2466 goto fail;
2467 mod = find_module(modname);
2468 if (!mod) {
2469 mod = new_module(modname);
2470 mod->from_dump = 1;
2471 }
2472 s = sym_add_exported(symname, mod, export_no(export));
2473 s->is_static = 0;
2474 sym_set_crc(symname, crc);
2475 sym_update_namespace(symname, namespace);
2476 }
2477 free(buf);
2478 return;
2479 fail:
2480 free(buf);
2481 fatal("parse error in symbol dump file\n");
2482 }
2483
2484 /* For normal builds always dump all symbols.
2485 * For external modules only dump symbols
2486 * that are not read from kernel Module.symvers.
2487 **/
2488 static int dump_sym(struct symbol *sym)
2489 {
2490 if (!external_module)
2491 return 1;
2492 if (sym->module->from_dump)
2493 return 0;
2494 return 1;
2495 }
2496
2497 static void write_dump(const char *fname)
2498 {
2499 struct buffer buf = { };
2500 struct symbol *symbol;
2501 const char *namespace;
2502 int n;
2503
2504 for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2505 symbol = symbolhash[n];
2506 while (symbol) {
2507 if (dump_sym(symbol)) {
2508 namespace = symbol->namespace;
2509 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n",
2510 symbol->crc, symbol->name,
2511 symbol->module->name,
2512 export_str(symbol->export),
2513 namespace ? namespace : "");
2514 }
2515 symbol = symbol->next;
2516 }
2517 }
2518 write_buf(&buf, fname);
2519 free(buf.p);
2520 }
2521
2522 static void write_namespace_deps_files(const char *fname)
2523 {
2524 struct module *mod;
2525 struct namespace_list *ns;
2526 struct buffer ns_deps_buf = {};
2527
2528 for (mod = modules; mod; mod = mod->next) {
2529
2530 if (mod->from_dump || !mod->missing_namespaces)
2531 continue;
2532
2533 buf_printf(&ns_deps_buf, "%s.ko:", mod->name);
2534
2535 for (ns = mod->missing_namespaces; ns; ns = ns->next)
2536 buf_printf(&ns_deps_buf, " %s", ns->namespace);
2537
2538 buf_printf(&ns_deps_buf, "\n");
2539 }
2540
2541 write_if_changed(&ns_deps_buf, fname);
2542 free(ns_deps_buf.p);
2543 }
2544
2545 struct dump_list {
2546 struct dump_list *next;
2547 const char *file;
2548 };
2549
2550 int main(int argc, char **argv)
2551 {
2552 struct module *mod;
2553 struct buffer buf = { };
2554 char *missing_namespace_deps = NULL;
2555 char *dump_write = NULL, *files_source = NULL;
2556 int opt;
2557 int err;
2558 int n;
2559 struct dump_list *dump_read_start = NULL;
2560 struct dump_list **dump_read_iter = &dump_read_start;
2561
2562 while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) {
2563 switch (opt) {
2564 case 'e':
2565 external_module = 1;
2566 break;
2567 case 'i':
2568 *dump_read_iter =
2569 NOFAIL(calloc(1, sizeof(**dump_read_iter)));
2570 (*dump_read_iter)->file = optarg;
2571 dump_read_iter = &(*dump_read_iter)->next;
2572 break;
2573 case 'm':
2574 modversions = 1;
2575 break;
2576 case 'n':
2577 ignore_missing_files = 1;
2578 break;
2579 case 'o':
2580 dump_write = optarg;
2581 break;
2582 case 'a':
2583 all_versions = 1;
2584 break;
2585 case 'T':
2586 files_source = optarg;
2587 break;
2588 case 'w':
2589 warn_unresolved = 1;
2590 break;
2591 case 'E':
2592 sec_mismatch_fatal = 1;
2593 break;
2594 case 'N':
2595 allow_missing_ns_imports = 1;
2596 break;
2597 case 'd':
2598 missing_namespace_deps = optarg;
2599 break;
2600 default:
2601 exit(1);
2602 }
2603 }
2604
2605 while (dump_read_start) {
2606 struct dump_list *tmp;
2607
2608 read_dump(dump_read_start->file);
2609 tmp = dump_read_start->next;
2610 free(dump_read_start);
2611 dump_read_start = tmp;
2612 }
2613
2614 while (optind < argc)
2615 read_symbols(argv[optind++]);
2616
2617 if (files_source)
2618 read_symbols_from_files(files_source);
2619
2620 /*
2621 * When there's no vmlinux, don't print warnings about
2622 * unresolved symbols (since there'll be too many ;)
2623 */
2624 if (!have_vmlinux)
2625 warn("Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped.\n");
2626
2627 err = 0;
2628
2629 for (mod = modules; mod; mod = mod->next) {
2630 char fname[PATH_MAX];
2631
2632 if (mod->is_vmlinux || mod->from_dump)
2633 continue;
2634
2635 buf.pos = 0;
2636
2637 err |= check_modname_len(mod);
2638 err |= check_exports(mod);
2639
2640 add_header(&buf, mod);
2641 add_intree_flag(&buf, !external_module);
2642 add_retpoline(&buf);
2643 add_staging_flag(&buf, mod->name);
2644 err |= add_versions(&buf, mod);
2645 add_depends(&buf, mod);
2646 add_moddevtable(&buf, mod);
2647 add_srcversion(&buf, mod);
2648
2649 sprintf(fname, "%s.mod.c", mod->name);
2650 write_if_changed(&buf, fname);
2651 }
2652
2653 if (missing_namespace_deps)
2654 write_namespace_deps_files(missing_namespace_deps);
2655
2656 if (dump_write)
2657 write_dump(dump_write);
2658 if (sec_mismatch_count && sec_mismatch_fatal)
2659 fatal("Section mismatches detected.\n"
2660 "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2661 for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
2662 struct symbol *s;
2663
2664 for (s = symbolhash[n]; s; s = s->next) {
2665 if (s->is_static)
2666 warn("\"%s\" [%s] is a static %s\n",
2667 s->name, s->module->name,
2668 export_str(s->export));
2669 }
2670 }
2671
2672 free(buf.p);
2673
2674 return err;
2675 }
Linux with added FPC-III support